How to group by the each week upto last six week s

Currently am working on the report. What i need is sample table,

Instance Type   Sep-23  Sep-16  Sep-09  Sep-02  Aug-26  Aug-19
-------------------------------------------------------------------------
Early ASN        4        2      4        1       1       2
Late ASN         2        1      5        3       1       1
     Sum         6        3      9        4       2       3

But the Actual Table is,

SPGI01_INSTANCE_TYPE_C  SPGI01_CREATE_S
--------------------------------------------------------------
Early ASN                9/17/2012 12:00:00.000
Early ASN           9/18/2012 10:06:11.000
Early ASN           9/19/2012 8:00:04.000
Early ASN           9/20/2012 3:00:05.000
Early ASN           9/10/2012 12:00:07.000
Early ASN           9/11/2012 12:00:32.000
Early ASN           9/3/2012 12:00:17.000
Early ASN           9/4/2012 10:06:00.000
Early ASN           9/5/2012 8:00:00.000
Early ASN           9/6/2012 3:00:00.000
Early ASN           8/31/2012 12:00:00.000
Early ASN           8/26/2012 12:00:00.000
Early ASN           8/14/2012 12:00:00.000
Early ASN           8/15/2012 12:00:00.000
Late ASN            9/17/2012 12:00:00.000
Late ASN            9/18/2012 10:06:00.000
Late ASN            9/11/2012 12:00:00.000
Late ASN            9/3/2012 12:00:00.000
Late ASN            9/4/2012 10:06:00.000
Late ASN            9/5/2012 8:00:00.000
Late ASN            9/6/2012 3:00:00.000
Late ASN            9/6/2012 2:00:00.000
Late ASN            8/31/2012 12:00:00.000
Late ASN            8/31/2012 12:00:00.000
Late ASN            8/31/2012 12:00:00.000
Early ASN           8/15/2012 12:00:00.000

I need to group by the "SPGI01_INSTANCE_TYPE_C" column and group the each week sunday upto last six week sundays.Here i pasted two sample tables one table is what i want and another table is what i have. Give me the solution for this.

My query is,

SELECT distinct I01.[SPGI01_INSTANCE_TYPE_C],
count (I01.[SPGI01_INSTANCE_TYPE_C])
  FROM [SUPER-G].[dbo].[CSPGI01_ASN_ACCURACY] I01,
  [SUPER-G].[dbo].[CSPGI50_VALID_INSTANCE_TYPE] I50

where
I01.[SPGA02_BUSINESS_TYPE_C] = 'prod'
and
I01.[SPGA03_REGION_C] in( 'ap','na','sa','eu')
and 
I01.[SPGI01_SUB_BUSINESS_TYPE_C] = 'PRD'
and
(I01.[SPGI01_CREATE_S] between '2012-01-01 12:00:00.000' AND DATEADD(day , 7, '2012-01-15 00:00:00.000'))

and
I01.[SPGI01_EXCEPTIONED_F] = 'N'
and
I01.[SPGI01_DISPUTED_F] != 'Y'
and
I50.[SPGI50_INSTANCE_TYPE_C] = I01.[SPGI01_INSTANCE_TYPE_C]
and 
I50.[SPGA04_RATING_ELEMENT_D] = 1
group by I01.[SPGI01_INSTANCE_TYPE_C]

I made a few assumptions about the data that you posted.

First, the values you posted all state the year as 2011 but the final end dates as column headers do not correspond to 2011, they are the Sunday values for 2012 so I altered the data. Also the final entry of Early ASN 8/15/2011 12:00, I believe is supposed to be a Late ASN entry otherwise the totals to do match up.

To get the results, you want you will want to apply the PIVOT function. This function allows you to aggregate the values and then convert them to columns.

SET DATEFIRST 1 -- set this so the start of the week is Sunday
select InstanceType,
  sum([39]) as Sep_23, 
  sum([38]) as Sep_16, 
  sum([37]) as Sep_09, 
  sum([36]) as Sep_02, 
  sum([35]) as Aug_26, 
  sum([34]) as Aug_19
from
(
  select SPGI01_INSTANCE_TYPE_C as InstanceType,
    [39], [38], [37], [36], [35], [34]
  from
  (
    select SPGI01_INSTANCE_TYPE_C,
      DatePart(wk, SPGI01_CREATE_S) WeekNo,
      DATEADD(DAY, 7 -DATEPART(WEEKDAY,SPGI01_CREATE_S),SPGI01_CREATE_S) WeekEnd
    from table1
  ) x
  pivot
  (
    count(WeekEnd)
    for weekno in ([39], [38], [37], [36], [35], [34])
  ) p
) x1
group by InstanceType with rollup

See SQL Fiddle with Demo